Abrasive article and method of making



Feb. 5, 1946. J PREN'HCE 2,394,478

ABRASIVE ARTICLE AND METHOD OF MAKING Filed Dec. 3, 1943 INVENTOR. MA/E514. PEtW 7705 EETI'ORNEY. I

PM Feb. s, 1946 UNITED STATES snassrvn ARTICLE AND METHOD OI BAKING 'l'heflarborundum company, Niagara Falls,

N. Ysaoorporationofbelawaro DcoanberSJMBsrIaIRoJIZ-HS C(lhlms.

This invention relates to the manufacture of composite articles and to compositions forand methods of uniting or combining the components thereof, as well as the products resulting therefrom. It is especially adaptable and pertinent to the manufacture of bonded abrasive articles, and more particularly to the manufacture of composite abrasive articles. as for example, bended abrasive bodies provided with metallic or other external supporting means such as metal backhis plates or elements, or side plates secured to the list faces of the abrasive bodies The invention has been found particularly applicable to the making of disc-shaped grinding wheels adapted to be mounted for grinding with the flat side face of the wheel. Therefore. for the purposes of simplicity and clarity, the invention will be described mostly as it applies to the making of such disc wheels. It is to be understood. however, that the invention can be similarly employed more broadly for the manufacture of other composite articles in which the components are united by means of solid ti bond layers.

In the manufacture of abrasive articles. such as the above-mentioned side-grinding discs having a rigid backing attached thereto, it is essential not only that the bonded abrasive body be secured to the supporting element with sul'licient tenacity to withstand the high stresses and strains to which it is subjected in grinding operations but it is also desirable, if not even essential, that the intervening layer of material, herein referred to as the "tie bond or "tie bond layer," be of sumcient thickness and elasticity or resilience to absorb or dampen the mechanical shocks of s'rinding instead of transmitting them to the backing and thence to the machine upon which the abrasive article is mounted or to the operator. Such supporting elements should also be secured by a means which will retain its strength at high temperatures and thus stand up under the heat generated during heavy duty grinding. It is further desirable that the material be resistant to water and the various hydrocarbon coolants used in wet a I a 2 The above combination of properties has been approached in the past by attaching the supporting elementto the bonded abrasive body by means of an intermediate layer of natural or synthetic rubber of appreciable thickness, the latter being secured by means of one or more coatings of a liquid adhesive or cement applied to both the backing element and to the bonded abrasive body prior to combining the various parts of the article. It has been found necessary to use a iiuuidad- 311% with all substagces heretofore zmlpioyed as intermediate ln ns layer in er to obtain a or a hesi n or the combining layer to the abrasive body and to the fthaslongbeenthedeslr i m which unite two surfaces by means of an intermediate layer of resilient material. as for example theattachmcntofa l backlngplatetothe side face of a bonded abrasive grinding wheel, to accomplish an adequately high strength oi union without the use of auxiliary adhesives or cements. The wide variety of cements marketed for such adhesive purp ses is indicative of their widespread use in this type of application where hlshadhcsionstrensthsare. Theideal way. heretofore unattained, of promoting high tensile strengths of adhesion would be to have a tie bond of such composition as to provide the desired adhesive qualities by reason of the ingredients contained therein so that the use of auxiliary cementing adhesives could be avoided.

The present invention provides such a means and method for combining the components of composite articles, as for example, securing rigid elementssuchasbackingplatesandtbeliketo bonded abrasive bodies in which the preliminary application of liquid adhesives or cements to the surfaces to be combined is eliminated and at the sametimethetensilestrensthsoladhcslonhetween the intermediate tie bond layer, the rigid supportingelementandthehondedabrasivebody is as great as, and even greater. than those obtained by the methods heretofore used which included, as an essential step, the application of liquid adhesives and cements for the purpose oi In accordance with the invention a rigid a supporting element is secured to a bonded abrasive body or in its broader aspects, the components of other composite articles of manufacture. are

secured. by means of an intermediate bonding.

' 50 to be combined without the application of liquid adhesives or cements to the combining surfaces or to the tie bond material, and without requiring any other preparation of the combining surfaces other than that required to put the surfaces semacleancondition. Whensocomposedandap-' plied in accordance with the present invention thetiebondlayerisstronglyadherenttoboththe abrasive body and the supporting means, possesses the n resilience and elasticity to ooabsorbgrlndingshomandretslnsthegrcater partofitsstrengthandresilienesinthepresence ofeoolingagentsandallraliesaudtheseveretemperamresoftenpresentinwetanddrysrinding operations.

In the drawing, which illustrates one embodiment of the invention:

l'igurelrepresentsafrontplanviewofadiscshaped grinding wheel embodying the present invention: and

Figure 2 is a sectional view taken along the line 11-11 of Figure l.

The disc-shaped grinding wheel illustrated in Figures 1 and 2 consists of a bonded abrasive section 0 of any desired thickness and diameter. having a flat grinding face 8 and an opposite supportingfaoe 1'. Theabrasive section lis composed of abrasive grain such as crystalline aluminum oxide, silicon carbide. or other granular abrasive material of the desired grit size or sizes,

suitably bonded. The bond may be'a vitrified oeramicmaterial, or it may be a silicate, or a resin or a natural or synthetic rubber compound. Asasupporttoprovideameansformounting, the abrasive section I is provided with a steel backing plate I attached to the supporting face Ioftheabrasivesectlonlbymeansofanintermediatel yeroitiebonds. Thetiebond sissecuredtotheabrasivesectionlandmetal plate 8 with adequate strength of adhesion thereto without the application of any auxiliary adhesiveeoatingstothetiebondlayerortothe supporting face 1 of the abrasive section or the inner face ll 01' the steel plate prior to assembly. Thebackingplatelisprovidedwitha centerarborhole ii andthrcebolthoies II for fastening the backed wheel to a mounting plate on the grinding machine. (The mounting plate is not shown.)

As the above description and drawings show.

thetypeotbondusedintheabrasivesection: results have been obtained with resin. vitrified, silicate and rubber-bonded The abrasive sections are methods of making bonded abrasive shapes. The abrasive section of the specific wheel illusresilient material in the form 0! a thin sheet approximately s r" to ss" in thickness. although the thickness may vary somewhat from these figures. By selection of the proper composition and thickness of this intermediate layer. the desired degree of resilience, i. e., resistance to mechanical shock, of the wheel can be closely controlled. A satlsiactory tie bond composition for carrying out the present invention comprises polychloroprene and a phenolic resin of the phenol formaldehyde resinous condensation type properly compounded by the addition of substantial amounts or a filler such as soft carbon black, and the other customary compoundins ingredients such-as vulcanizing agents, antioxidants. stabilizers, plasticizers and the like. It has been found that imsatisfactory results the phenolic resin should be incorporated into the polychioroprene in the form of a liquidresin; a phenolic resin such as that sold by the Bakelite Corporation under the trade designation of liquid Bakelite resin No. BR 10190 has been found highly satisfactory. Another liquid phenolic resin suitable for use herein is vacuum liquid resin No. 925 A sold by the Var-cum Chemical Corp. 01 Niagara Falls, New York. Fillers which may be used to replace part or all of the soft carbon black include. for example,

channel black or mineral fillers such as blanc iixe, natural whiting, Dixie clay and the like, although soft carbon black is the preferred filler and produces the best results. Also, a part of the polychloroprene can be replaced by a natural or a reclaimed rubber.

A tie bond material comprising mlyohloroprene andaliquid phenolicresin.whichishighlysatisfactory iortheprescntpurposesismadeofthe following ingredients compounded and sheeted tothe desired thickness on aroiimill.

Parts by weight Polychloroprene 100.0 liquid phenolic resin (Bakelite BR 10100) 5.0 Soft carbon black. 100.0 Hard carbon black 50.0 Light melnad u in (.6 zinc oxide 5.0

Neosone D (phenyl-beta-naphtbylaminc)- Stearic acid Sulphur .60 Ciroo (light process) 011.................... 5.0

Partl tweisht Polychloroprene 100.0 Liquid phenolioresin (Bakelite BR 10100)-.. 20.0 Soft carbon black 150.0 Extra light calcined magnesia 4.0 Zine oxide 2.0 Sulphur 0.5 Alta: hide) 1.0

hensothlasyl disulp Neosone D (phenyl-beta-naphthlamine)-- 1.0

Anotheresampleofatiebendeom position tiebondeonshtaofalayarolmpliable. 'llembodyingtheprosentinvsntionandwhichhas were 8 bemioundsetlsiaetoryinuleistba'tgiven reeulte'inaainereeeedtaeterotmietystnor below. mal aerating speeds and also permits at higher 1 w Partebyweight speeds at operation when dedrebie. Abe by e 100.0 reason oi the high heat M or the tie isquidphenolicreeinivareum #0254)--- 8.0 I bendmsterlshmuchclthehesteeneratedin 80ft carbon blaok.---- 100.0 the'abreeive section during use is quickly can- Hard carbon bieek..-------------------- 50b dusted through the tie bond layer to the rigid light camped magneeis.............. 4.0 support, where it h more easily dissipated by zinc oxide 5.0 rediatiomthueremovingmuehoithedangsroi Reasons D (phenyl-beta-naphthylamine)- 1.0 l0 localised build-up oi heat in the abradve por- Btearlcacid l.0 flons with its consequent increase in etrenes Sulphur .5 which tendte break the wheel. i mm mfir m t an Afteratiebondeompositionsuehaeoneoi m lsergymfeaturevmichis lyimpcrtsntin mammmmmmnmmm" grindingwheelswhichintheproeeeeoigrinding square inch, and usually 150 pounds per square inch, at a temperature or 275425 1'. usually at about 300' 1''. Thirty minutes is usually suihcient toadequatelvcurethetiebond. Forbestresuits, the tie bond should be cured always under a pressure and temperature 'suiilcient to cause it toextrudesliuhtlyattheedgesirombetweenthe backing plate and the abrasive body.

The development of a means and method for attachingbondedabrasivebodiestorigidsuporting elements, such as the mounting of disc side-grinding wheels on metal backing pistes without the use of an auxiliary cementing adhesive as provided by the herein-described invention is a distinct advance in the manuiacture of articles of this type. The elimination of cementing removes the variables of cements and their application, which are a potential source of error unless properly supervised at all times. Any which reduces man hours is highly desirable, when the quality of the ilnal product is not only maintained but even improved, as is the case with the present invention. The present means and method of securing bonded abrasive bodies to rigid supports decreasesthecostoi'mountingbyareductionin labor, by a simplification of operations, and by a reduction in the amount of materials used. Too. the parts alter preparation do not require immediate bling. but can be stored for later assembly at the convenience of the operator and availability at Also, in curing the present articles, the temperature and pressure of cure can be varied considerably without the danger of overcuring and its resultant loss of strength. These and other features lead to economics of manufacture not heretofore attainable.

Abrasive wheels and discs of the present invention several beneficial and enhanced properties which extend their field oi usefulness. For example, the present abrasive wheels have a long temperature range of serviceability extending from -30 to 300 Fahrenheit. Their retenoihighstrengthandresistaneetotheshocksof grinding and can endure severe operating conditime It is not intended that the invention should be limited to the particular embodiment of wheel illustrated, as like objects and advantages are obtained in various other abrasive articles where it is to secure bonded abrasive sections to metal or other rigid supporting or mounting means. l'orinstancasimilardiscwheelseanbe shsped side grinding abrasive wheels, it is not to beconetruedasbeinglimitedthereto, lnits broaderaspectsitlsuseiulintheunltingorcombining of components of various other composite articles of manufacture. For example, itis suitableforuseintheproductionoflaminatedprodacts such as in the manufacture oi laminated metalsheetsinwhichtwoormorelayersoia metal or an alloy 01' the same or different compositionsinsheeti'ormareunitedto provldeacomposite metallic sheet; or. similarly, the present invention is applicable to the formation of other laminated sheet products in which the various laminations may be the same or diflerent materials and may be fabric, wood such as in plywood, metal, or ceramic in nature. Also, the invention can be adapted for the combining or various elements oi. composite articles such as the attachment of the backing or supporting elements, mountings. handles and the like to the functional elements oi the products to provide the desired iinal articles.

Having described the invention full it is desired to claim:

1. A bonded abrasive article having a supporting element and a bonded abrasive body. the supporting element thereof being secured to the bonded abrasive body by a tie bond layer containing as an essential ingredient a substantial proportion of a mixture of polychloroprene and aphenolicresin,the roportionoiphenoiicresin tionofmechanicalstrens i s ll I being 140% basedonthepolychloroprene.

4 amen llhlnommh flflllfllldnmcouleltooodberewithtenocltytotheboudod pol-Hammad thereto. onsfllontflo obrsuvebodyondthemportlnonloto. hondhstusnthommotlnomeomondthe mAmethodotsecurin srkidmppou-nng shrsd vobodyoonhlnlnluonoslmflollnlredlontosuhssontislmportlonolomlxtureot 8 oommoelnoertincosheetotunmiosmssdflo oudophmololoehydorelln. boudmotu-lsloonstsflnzcslmflolly l'mly- Certificate of Correction Potent No. 2,394,478. February 5; 1946.

JAMES A. PRENTICE It is hereby certified that errors appear in the printed specification of the above numbered potent requiring correction as follows: Page 2, second column lines 23-24, for the word "Vocuum read Vorcum; page 4, first column, line 6, 2, after resin strike out the eriod and insert instead the profirtian g phenolic main time said 1-809'booedonlln oyohloroprmusndthot tters otentshouldbe withaieseoorrectiol is therein thotizhe some moyconformfiothereoordofthecose in the Patent Oflice.

signedmdlesledthislstdoyofootobmLD. 1946.

LESLIE manna-woman 4 amen llhlnommh flflllfllldnmcouleltooodberewithtenocltytotheboudod pol-Hammad thereto. onsfllontflo obrsuvebodyondthemportlnonloto. hondhstusnthommotlnomeomondthe mAmethodotsecurin srkidmppou-nng shrsd vobodyoonhlnlnluonoslmflollnlredlontosuhssontislmportlonolomlxtureot 8 oommoelnoertincosheetotunmiosmssdflo oudophmololoehydorelln. boudmotu-lsloonstsflnzcslmflolly l'mly- Certificate of Correction Potent No. 2,394,478. February 5; 1946.

JAMES A. PRENTICE It is hereby certified that errors appear in the printed specification of the above numbered potent requiring correction as follows: Page 2, second column lines 23-24, for the word "Vocuum read Vorcum; page 4, first column, line 6, 2, after resin strike out the eriod and insert instead the profirtian g phenolic main time said 1-809'booedonlln oyohloroprmusndthot tters otentshouldbe withaieseoorrectiol is therein thotizhe some moyconformfiothereoordofthecose in the Patent Oflice.

signedmdlesledthislstdoyofootobmLD. 1946.

LESLIE manna-woman 

